KTN80 confers precision to microtubule severing by specific targeting of katanin complexes in plant cells

Wang, Chaofeng; Liu, Weiwei; Wang, Guangda; Li, Jun; Dong, Li; Han, Libo; Wang, Qi; Tian, Juan; Yu, Yong; Gao, Caixia; Kong, Zhaosheng

doi:10.15252/embj.201796823

Cited by 49 publications

(72 citation statements)

References 49 publications

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“…We therefore focused on the microtubule severing protein complex KATANIN (KTN), which is important for secondary wall production and microtubule alignment (Burk et al 2001; Stoppin-Mellet et al 2007). The KTN complex is a hexamer of KTN1-KTN80 heterodimers (Wang et al 2017). The single copy of KTN1 is responsible for microtubule severing whereas four KTN80 isoforms confer targeting to microtubule crossovers.…”

Section: Resultsmentioning

confidence: 99%

Long-term single-cell imaging and simulations of microtubules reveal driving forces for wall pattering during proto-xylem development

Schneider

Klooster

Picard

et al. 2020

Preprint

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42Plants are the tallest organisms on Earth; a feature sustained by solute-transporting 43 xylem vessels in the plant vasculature. The xylem vessels are supported by strong 44 cell walls that are assembled in intricate patterns. Cortical microtubules direct wall 45 deposition and need to rapidly re-organize during xylem cell development. We 46 established long-term live-cell imaging of single Arabidopsis cells undergoing proto-47 xylem trans-differentiation, resulting in spiral wall patterns, to investigate the 48 microtubule re-organization. The initial disperse microtubule array rapidly readjusted 49 into well-defined microtubule bands, which required local de-stabilization of individual 50 microtubules in band-interspersing gap regions. Using extensive microtubule 51 simulations, we could recapitulate the process in silico and found that local 52 recruitment of microtubule-bound nucleation is critical for pattern formation, which we 53 confirmed in vivo. Our simulations further indicated that the initial microtubule 54 alignment impact microtubule band patterning. We confirmed this prediction using 55 katanin mutants, which have microtubule organization defects, and uncovered active 56 KATANIN recruitment to the forming microtubule bands. Our combination of 57 quantitative microscopy and modelling outlines a framework towards a 58 comprehensive understanding of microtubule re-organization during wall pattern 59 formation. 60 61 62The plant vasculature contains xylem cells that are organised in interconnected 63 tubular networks to enable efficient water distribution to plant organs, and that 64 support plant stature (Myburg et al. 2001). All plant cells are surrounded by primary 65 cell walls, which dictate growth direction. Xylem cells are reinforced by an additional 66 wall layer, referred to as a secondary wall, that is deposited in local thickenings that 67 form highly ordered spatial patterns (Turner et al. 2007). Xylem cells subsequently 68 undergo programmed cell death, which leads to the clearing of their cytoplasmic 69 content and the resulting formation of a hollow tube that provides the water-70 conducting capacity of vascular plants (Meents et al. 2018).71 The major load-bearing component of plant cell walls is cellulose; a β-1,4-72 linked glucan. Cellulose is synthesised by cellulose synthase (CESA) complexes 73 (CSCs) that span the plasma membrane (Schneider et al. 2016). Nascent cellulose 74 chains coalesce via hydrogen bonds, get entangled in the cell wall and further 75 synthesis thus forces the CSCs to move in the membrane (Diotallevi and Mulder 76 4 2007). The CSC delivery to, and locomotion within, the plasma membrane is guided 77 by cortical microtubules that presumably are associated with the plasma membrane 78 (Paradez et al. 2006; Crowell et al. 2009; Gutierrez et al. 2009; Watanabe et al. 79 2015). Cortical microtubules thus directionally and spatially template the cellulose 80 synthesis machinery during cell wall deposition. 81Microtubules undergo dynamic re-organizati...

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Section: Resultsmentioning

confidence: 99%

Long-term single-cell imaging and simulations of microtubules reveal driving forces for wall pattering during proto-xylem development

Schneider

Klooster

Picard

et al. 2020

Preprint

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“…Previously, we reported that the augmin complex recruits the g-tubulin complex to preexisting microtubules and initiates microtubule nucleation [7]. Moreover, we described how an intricate interaction between the katanin p60 subunit KTN1 and the p80 subunit KTN80 confers precise microtubule severing at either microtubule branching nucleation sites or crossovers [8]. Here, we observed that augmin preferentially localizes to microtubule crossovers.…”

mentioning

confidence: 53%

Augmin Antagonizes Katanin at Microtubule Crossovers to Control the Dynamic Organization of Plant Cortical Arrays

Wang

Liu

et al. 2018

Current Biology

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Plant cells do not possess centrosomes, which serve as the microtubule organizing center in animal cells; how plant cell microtubule arrays are established and maintain their dynamics remain poorly understood [1]. The γ-tubulin complex and the katanin complex play central roles in the organization of plant cortical microtubules [2-6]. Previously, we reported that the augmin complex recruits the γ-tubulin complex to preexisting microtubules and initiates microtubule nucleation [7]. Moreover, we described how an intricate interaction between the katanin p60 subunit KTN1 and the p80 subunit KTN80 confers precise microtubule severing at either microtubule branching nucleation sites or crossovers [8]. Here, we observed that augmin preferentially localizes to microtubule crossovers. Live-cell observations and analyses revealed that, whereas a small portion of crossover-localized augmin complexes act to trigger nascent microtubule nucleation, the majority function in stabilizing the architecture of microtubule crossovers. Finally, genetic analyses and computational modeling confirmed that suppression of augmin activity elevates microtubule severing frequency and facilitates the formation of aligned microtubule arrays. Combined, our findings reveal an unexpected role of augmin and demonstrate that augmin antagonizes katanin-mediated microtubule severing. Furthermore, we propose a novel mechanism for how augmin determines self-organization of plant cortical microtubules by preventing microtubule severing at crossovers in addition to triggering microtubule nucleation.

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“…Another example involves four loci encoding katanin p80 subunits ( KTN80.1 , KTN80.2 , KTN80.3 , and KTN80.4 ) in Arabidopsis . We designed three sgRNAs to simultaneously knockout all four KTN80 genes using CRISPR/Cas9 . The resulting quadruple mutant exhibited a severe dwarf phenotype, demonstrating that the four KTN80s act redundantly and providing genetic insight into the function of KTN80s during development in vivo.…”

Section: Crispr/cas9‐created Mutations In Plantsmentioning

confidence: 99%

CRISPR/Cas9‐Based Genome Editing and its Applications for Functional Genomic Analyses in Plants

2019

Small Methods

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The ability to modify complex genomes precisely to create specific mutants is the holy grail of basic research and applied genetics in the postgenomic era. Programmable sequence‐specific nucleases (e.g., zinc finger nucleases, transcription activator‐like effector nucleases, and clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR‐associated (Cas) systems (e.g., CRISPR/Cas9)), which induce targeted DNA breaks that are then repaired by endogenous repair machinery to generate mutants in a variety of organisms, are being developed at an unprecedented rate. Herein, this paper reviews the history, structure, and biological function of CRISPR/Cas systems, describing how it has been adapted for genome editing (especially CRISPR/Cas9, which has prompted a genome engineering revolution), and emphasizes recent applications and advances in the functional annotation of plant genomes and crop genetic improvement. In addition, the challenges of using the CRISPR/Cas9 system and strategies for improving its specificity are discussed. This review also introduces the creation of CRISPR‐edited DNA‐free plants, which may be more publicly acceptable than other genetically modified organisms. Finally, the future directions and applications of the CRISPR/Cas9 system are speculated on.

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KTN80 confers precision to microtubule severing by specific targeting of katanin complexes in plant cells

Cited by 49 publications

References 49 publications

Long-term single-cell imaging and simulations of microtubules reveal driving forces for wall pattering during proto-xylem development

Long-term single-cell imaging and simulations of microtubules reveal driving forces for wall pattering during proto-xylem development

Augmin Antagonizes Katanin at Microtubule Crossovers to Control the Dynamic Organization of Plant Cortical Arrays

CRISPR/Cas9‐Based Genome Editing and its Applications for Functional Genomic Analyses in Plants

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